Incorrect Handling of Bearer Token with trailing space in openidc_get_bearer_access_token

[gustoliv]

Summary

This PR improves the openidc_get_bearer_access_token function by trimming whitespace from headers and ensuring proper validation of the extracted access token. (Fixes #537)

Changes

• Added a trim function to remove leading and trailing whitespace from headers before processing.
• Changed the validation check from nil to "" since header:sub(divider + 1) always return a string.
• If the token is missing, it will be an empty string ("") rather than nil.
• This ensures invalid tokens are correctly identified.

Impact

These improvements enhance robustness and prevent potential issues with incorrectly formatted headers.

Test Results

After these changes, the unit tests improved from 498 successes / 11 failures to 503 successes / 0 failures.

Before:

After: